Vidal, Laura

Abstract Purpose: To determine the safety and feasibility of combining intratumoral reovirus and radiotherapy in patients with advanced cancer and to assess viral biodistribution, reoviral replication in tumors, and antiviral immune responses. Experimental Design: Patients with measurable disease amenable to palliative radiotherapy were enrolled. In the first stage, patients received radiotherapy (20 Gy in five fractions) plus two intratumoral injections of RT3D at doses between 1 × 108 and 1 × 1010 TCID50. In the second stage, the radiotherapy dose was increased (36 Gy in 12 fractions) and patients received two, four, or six doses of RT3D at 1 × 1010 TCID50. End points were safety, viral replication, immunogenicity, and antitumoral activity. Results: Twenty-three patients with various solid tumors were treated. Dose-limiting toxicity was not seen. The most common toxicities were grade 2 (or lower) pyrexia, influenza-like symptoms, vomiting, asymptomatic lymphopenia, and neutropenia. There was no exacerbation of the acute radiation reaction. Reverse transcription-PCR (RT-PCR) studies of blood, urine, stool, and sputum were negative for viral shedding. In the low-dose (20 Gy in five fractions) radiation group, two of seven evaluable patients had a partial response and five had stable disease. In the high-dose (36 Gy in 12 fractions) radiation group, five of seven evaluable patients had partial response and two stable disease. Conclusions: The combination of intratumoral RT3D and radiotherapy was well tolerated. The favorable toxicity profile and lack of vector shedding means that this combination should be evaluated in newly diagnosed patients receiving radiotherapy with curative intent. Clin Cancer Res; 16(11); 3067–77. ©2010 AACR.

Abstract Purpose: To determine the safety and feasibility of daily i.v. administration of wild-type oncolytic reovirus (type 3 Dearing) to patients with advanced cancer, assess viral excretion kinetics and antiviral immune responses, identify tumor localization and replication, and describe antitumor activity. Experimental Design: Patients received escalating doses of reovirus up to 3 × 1010 TCID50 for 5 consecutive days every 4 weeks. Viral excretion was assessed by reverse transcription-PCR and antibody response by cytotoxicity neutralization assay. Pretreatment and post-treatment tumor biopsies were obtained to measure viral uptake and replication. Results: Thirty-three patients received 76 courses of reovirus from 1 × 108 for 1 day up to 3 × 1010 TCID50 for 5 days, repeated every four weeks. Dose-limiting toxicity was not seen. Common grade 1 to 2 toxicities included fever, fatigue, and headache, which were dose and cycle independent. Viral excretion at day 15 was not detected by reverse transcription-PCR at 25 cycles and only in 5 patients at 35 cycles. Neutralizing antibodies were detected in all patients and peaked at 4 weeks. Viral localization and replication in tumor biopsies were confirmed in 3 patients. Antitumor activity was seen by radiologic and tumor marker (carcinoembryonic antigen, CA19.9, and prostate-specific antigen) evaluation. Conclusions: Oncolytic reovirus can be safely and repeatedly administered by i.v. injection at doses up to 3 × 1010 TCID50 for 5 days every 4 weeks without evidence of severe toxicities. Productive reoviral infection of metastatic tumor deposits was confirmed. Reovirus is a safe agent that warrants further evaluation in phase II studies.